SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '89305d0ec281154bf9da28053b7dc225fd7de33c4e58f59d9f80afb07a2586d8' 
  AND token = '7Pz4kyZL+mzYjQ8vYMpfUXvx4YSatlmmTEYdPRqIYoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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