SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c27f5ac4dc9f056a18e441a9902cba025633afa96181eb7ecd589f96927c0d51' 
  AND token = 'CBpsv++ce2CfvXMsCxjrf42YJB7FzJ3terkLBB6G0Ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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