SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a6cf40f2121e944e689920305c758ae086d8c656d4ac973b107edb3a0af8867f' 
  AND token = 'tJQ1KQdA1MR+gjxwaRQNSrokC3DSV9HrM2UoJu0q+YI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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