SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38be77b9d08967661d4ef6048ca22841f907e3fc3037f2e52166e0e8344d867d' 
  AND token = '/pKtsZQOE2Q5qRm1B+3FT5LM4gVsuoNEsulw6/hI+xM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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