SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bb5635fbfb3992dd5d556651b640e3789b04ff4be4c4b00d142425887e42c91a' 
  AND token = 'BkHp+9VQj+MRQp/pM5OUTc+qSlf48lWrWWgeMZyZYGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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