SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a44c2d8a7551c696e463bc8d8c1e87c6721e75409cd63e16d8491fe692592c1' 
  AND token = 'aMCMHG6Zn4p6EKa7v0UnFmDgdwYB5gzpJ7QZ+JGKNXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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