SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f6ac75266ff9bdf88a4eb89fa77faaee29ef3a142fe3766b517bc7912cd40e9' 
  AND token = 'aI14jI+DdjqYJzsyOYN/ipeMGbpJd74zTOT8HfNbXMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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