SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '75a94387833922c426c285cf61a7a4a3e332eb9f5dcadb04859ab58c36d74068' 
  AND token = 'EBthmI+N3bnCmPbUMB2JX9MC+gNxbvwOP7botvVbqQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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