SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ac1b8646a9e1ac51792572b9245029ffdb34f96cd3805c50e518c558bde827f' 
  AND token = 'mB9diweISQ2+kgjS4n1sZni16fGJLSfmP03mJ9J2+rc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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