SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcc3ccbb3114c0265103a2798cfde14af624af881be81994baac7f9e3199d5ea' 
  AND token = 'UHe5odNg1QaYW5B4Qo+RoMLVCJ34xk/otYkKIK+Jfgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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