SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b51f4572af09a26dfa522d49d65674836fede187bb105bc242f577902d8527da' 
  AND token = 'nChf9Kgyi97wLiNGPubk6bHLRZH4stP7hNfQgVpzuv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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