SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0542f3a57c8c94a42caeeb1c39e9942a69db81016fe49480661929c8465e9fc0' 
  AND token = 'nhdrHM9qYYBtfxmR36LHxbxIua0UFV9QtaxGCaxwpyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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