SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77745f4013431eb688b71636258ea9f742977fa73b2d639d45ca29853da52124' 
  AND token = '7svCRCYvcOBsusfxzRQsD0qkOvVpmi7zGVSVoZfG3Cg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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