SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1201f29d5b72da64371ecc4bfb0bcad2ce6c848d27c3c0757128497ae6841adf' 
  AND token = 'iF63GN9zRD4rYsR6+MUThU17g1oz6z8q3YcP5KldTPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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