SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa75ba7173c3b1a27d0920027f6fc49ac1e682a939b905f9d0e4526a7c27ee66' 
  AND token = 'iAvAb3OF6oweZLmqSDD6lzNFjfoNV3ML35Zwg1vzgI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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