SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a78f5c929c62069cc5925b180233271155a0c1098b7defdf7f90c4545379f736' 
  AND token = 'aQbMhfSOXc+56ELfWtREhJoD6OHpnqglwRcGvF5uZLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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