SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e88a7f88752e041c3d723aa4b8310fc22b652d6795ec7e0813ff728f0d821150' 
  AND token = 'O0uOuKKQHTq9mos/qj+9zVIbNnJvFWrrG45i5FtQWNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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