SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ac8a78fd845671d93a54b9eff7116213ccacc48293e4c82ddbe7615b21ec8f8' 
  AND token = 'C0RL1qugaJIfuw97RvTh6BGp5f8oo+C+6Q1bWzLMYPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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