SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f3d10ba3ca24922ae893719092249bfbff2739568feb5d959f0be674500ab75' 
  AND token = 'QAmUpAET1V7tiFRn9lRxuTywwCNjZoWz/VnqYZ7xFqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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