SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d66fc40fe90ecd944353c2cb93874c6daf57c222f3aeaadd5616ae06140d055' 
  AND token = 'M0/V8kUZpXYrXjoJe8zVtQ3fqz3wSOP/MI1UAp7zzi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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