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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a53e33974910faa4ea36ca082409bfef78012f997ae30d38170181872699c802' 
  AND token = 'xy5UUtrlBhxmkgFIBLDglYz3TTB5UluRrNZvjCYH7vU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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