SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc18afb0be6dbe82a553103f27c4aee58b47272e567e0845f6d94beaa67c78b4' 
  AND token = 'DtAW7DQwZXaqva9SKG8EAkC4tSw1bMDpMDgKkw02N1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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