SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4084e37ed651713343a9ff2d2f5b09438922b447e60eab556dfb226b5a3b75c2' 
  AND token = 'ReUGuE8D+2A0/je7Uz3LXZGn6zswevK35GQZyJ2PRzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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