SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd7694995b17500b43ef9257dfb8ddbca09dad548cb66ba2cd6438642964c89b' 
  AND token = '517knVtZnudms6ey+suSbFl6kFO358i2gozmEV8QxXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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