SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26a50aebc4513981d03e7dbd49c999e114e67fa5e47c0be4c80e647c8b8d89c0' 
  AND token = 'RSgYOG2B9+wzmZ4PbWvbBsNdmZnAHkPmiCOr38Ewi1E=' 
  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"
    }
  }
}