SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c11cba1842541d579252e136052fb284faeb0ae312cdc2ec735dc7bbdf996fbd' 
  AND token = 'yn1ohA5oxNq1i9mQeblLcMJCcykpfOJzSmQLQvLGvoc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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