SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a93ec1328245bc9b366a61622168ac6fd213bf86b02b4ff1ea321d3ae8f5c8ac' 
  AND token = 'RThohN9rpGxaIiDDOQccRXIWNwFlUTxoRz/7O47wE8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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