SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2a8f5226a5afcf1b857cba4f3cb5f9df85ee876d117c55693bc430bdac14cd8' 
  AND token = 'U/7Ub32p4uD/QH6BpgALQw7B+Qgu08uPAOKiLvmQbFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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