SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a6c8f11711c5f1565098dfd13e58c767e913fa99035757f382586cff8ed17ed' 
  AND token = 'BYw2H145vj7qRoglIAaPhurRDDKFF9k/VMX0/u5Qjzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}