SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99b43c8b0e3425bbc0f37067059a14295690579be2331ba22b1d4fda82317e43' 
  AND token = 'TyW9BYvhn47l633Cyszj33tGECSEh4GuoAYEf5SEerQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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