SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b9a8770a2aa38191a830cce5dbf80e31258660c443e9258c68a9380d4ad585e' 
  AND token = '79kwTAaoVNFvECHRbczih93fwBUsf6HNtAkr9qtriG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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