SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a69e82d6b378274ab77afbb092c24aa7ac8f8be550cea00c446a80d18edf0a75' 
  AND token = '1LgnDrRY1UAzpv3Qq6FG/RCv+3pCraWlrCZyeszryuo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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