SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f0ce48acbf2a0d59dba0e2841290eab2d341867a5d53cabfd226d1b5478b683' 
  AND token = 'KwFuvgYtlgSCxKGOi+kS+aGaT9H/lioBLPFfAZwN6gI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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