SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f49ebdc8ba702d36365e4a27cce6342e8442ef0b977e6cad2e5d469329e0aab' 
  AND token = 'Pf4RzaQ7wRiRVCKEKqNWYUpbrr7YuKtVVGLMQgX0uSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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