SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e2bc2a0e268df74edaf8e755bdf5ef4faa7d581635c17fcaca002d3cb7904e9' 
  AND token = 'hLVH/L9u/zB6t+qkuVmlkvVcSP2NSsxjEGV6U66p8DY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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