SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63c268ac2b4dc26b53055ec35787914742ef95e15dc54edb83e2188d07d70afa' 
  AND token = 'I/OTxr5SE3tkZrS3S0i1pTdDg/rsvX2nEdQK+92nnJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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