SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40aee309811fe529d93cd58a77e59eafc8456197ea568e01724876aa365c697f' 
  AND token = 'pejUVN9RfYrag3LJLLYFRNxPTWBPv+ZKkqvF2bM2EJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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