SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '96876209ab793f678cf07fa741cc85727e8df2825188cc02fe8dd8797c8c064b' 
  AND token = 'OyhuGtZwfxyARVhHIGfdhZZ+bNDCTJE7gCp0PWwgU9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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