SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e73871c91478650e8213df4da6675954098da06916c37e12df731b9b3afd839b' 
  AND token = '6lsPod5IOV/ZNfHggJQAgRfxLQSPR2idf/0fz1ahzuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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