SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6428379b16d796e0b30f419660bd1fce8fd2c715263b9794909b76bf40c576d1' 
  AND token = 'FSEeSJEBlJTHAFh9BQZkJ/Wy18VqybTOPHL+mkvMwsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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