SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b8818f88b57c694a88fda536ac1241548944bf74245224298c63e9e2af74180d' 
  AND token = 'cF3v1T/uv9PmplcqpnXp6NYAFknSBXLeIUN6fKIO7Gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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