SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f3827e7e1dcf5111954249999f799010158051e562a6f823aceb251fd480dfa' 
  AND token = 'ludefMeqd97vPoYN59DTzssLwWInZIlE9ek6PonUPok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00111

JSON explain

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