SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1a3d0b1d2384110a375f168e8254a676381f30a450a9546fec3244ddf62024e' 
  AND token = 'sIrtxzlEoeJElzy1PkK7dKc+ndF2NSKmHyDxeTKBuqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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