SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59ac1701d7228bd3ef61754a1721faee9c0754c08e7fd85b96a48ad1262ee23c' 
  AND token = 'qoHEP9FCsNnqnxzsv7aZw33rOqztntyms/9VNVBb7Sw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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