SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c68b7fae1d417f36c39a72549ae3c3b95e15dde24b70ac1c5b7b36d7546322c5' 
  AND token = 'Ge2Mhv31lUowwpHT+nRbzDWDfNGj3tOnam+JJ6FlCig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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