SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c3fb29fe6f8326eb8018a71aa8a428cda84492df56b26a358386bbf7151bb25f' 
  AND token = 'zOIPAXTlxIKSAaODHsz/lKwHbTqB0jsEIqXtAuzdJdQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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