SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df02623263c001ba7c80d36227f3e315dc796a2aa5646948f144c42af2990e0f' 
  AND token = 'gvGw1Q9Pv54q11pJV4+u8YVHs7ylzOMRmQ1/EysK7zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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