SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c3ce957f20f58040b3bc948f174826d3227a166018200dfa4af85fbc609b2df' 
  AND token = 'RIVwljBfPER4EOtzkX54ClaqXmZStOQjeTACddPd+p8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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