SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37e2c893bbaabec9a226e9ac28e88f847b7c784e800b025c4f6591161ee939c6' 
  AND token = 'vzIY3Q6JTu9i0gFd5EW0Zy6ZEy40PKqzePVoKfH7oSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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