SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b425de0fa012f01c9014d15aec3c91ecb7ca1c69f49309d6e112837fc806ab0' 
  AND token = 'KrQLgp5gSYwf1Q/VmLzQbQCdsXxVpYoTJGQZ6cVY+Pc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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