SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc18a250f05e12f6523ca77a347144e21516aa1fa25c30ed3b539425aee62c76' 
  AND token = 'N0F7pJ1cRV/2iYPvietcWqCqd41KBFadOITbizVnIf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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