SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e82a27c4494e3c2692ecb400b2045b433d456d426f079fdcb8a9462ff99f260' 
  AND token = '0kBoTbUulEF2sI7XovyelMIgwiwjPMlihE46WbRQS6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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