SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90b0d09c1af1aeae7f696d6fa49a957118b4873d25e192f9487e4c22f3372dcb' 
  AND token = 'fbk4Ff6uYNG335TZ1uOl64HPIlu8vU6s85uZGTQE+Zc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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