SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5859886a2f74bc2e74424e4e9920c22138b5d2007bab51a24f222912a6c9b415' 
  AND token = 'ytRRKj9Rv9oQhS9zU6i67YhzdA/1Vwn+6PLzkKiJ6pM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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