SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c854ddd50357e82bfc9996da04fc1e72790276fda5075cf41d6d2f966076ecb' 
  AND token = '+3XWHVsZYbqVrd8zcJwwPNuJc7KE0KTiIK818qXXUQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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