SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b660f2c95daf446776e8dcc50599466f3a100f99cad435d143a0d51777597d8' 
  AND token = 'w0NiLrIiHeCksLDjm/Kup7mFJBdVvqpNdUKdwu2VfPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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