SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0fed61944224d8639f6afcdb7e1cb0328c30071758599b8af1c4cbc418428a2' 
  AND token = '51pA461MjN3Dq8autrLRd4XV075vVh7C1ksGSWIhrs4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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