SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c46bd2c8d02b7e39756fe6020b3dea1558c5a37eb637b71bf4be99f35e9bbde6' 
  AND token = 'dEawKJLBCgoac867ajB58Asdhf4yifKLSC32p4I5slw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}