SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c67d01afb5424cb03dd1f550c3754fed38c300d32d61133696b1eafc9168c048' 
  AND token = '4RZG5NWdhQ7yXyLhw4XCuzWKsQB9qAUobKkqvJ5XFkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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