SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '795ea717c73ce05d3718acaded0085f1ee7224e8616aa1ceb864e49b8f219163' 
  AND token = 'uFtVOznuJZIJ4fMBFHnJLAcQv+3VabiTgJh61c+WmTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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