SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bc41e8a3f0e5f65708d9475399640a732cc4a1ca513059fe4652b8dd6646b5a' 
  AND token = 'wfz7SYcT6ql0tMhF1sNl0jiFVRigVw2Ach6+bf2aMws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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