SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf89c13a17ce2049f29f2ad10aeb5d1f505155f15209e8a34f431631bdcabd7d' 
  AND token = 'c6Ft7rpOOS8ELYS6Igg1IrFtYakpArNgj4zmgth2P2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}