SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ef5473e82488a206c20bb63e4f2b61a1cddf7fb93df4b649555ade2939c7520' 
  AND token = 'xfrs50AbBVIv5wphtEcr4RPbUsCFjjHaHXXI6sOo8Fw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}