SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc9cdfce5a1d4e2cbb0a9ab36f6eb74915764bc19b76915740325bdda2df2be5' 
  AND token = 'Xhx8I5gqA0Z8TWaXfuVCgoE8qm6kBCDjSBYtukcXppQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00082

JSON explain

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