SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a56bbd7bb9d4e3b41b2a590aa189d9521699a3a5e822ac23c0b423caddf39498' 
  AND token = '6+QkEDz1o04Ov1VdGdfHKPQ1i9iypyVrW9ieL4LXMj0=' 
  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"
    }
  }
}